Multiple switches on network causing a problem?

[KeithOwen]

Hi all,

I have an issue maybe someone can help me with...

My Internet access comes into the house via a cable modem from my ISP. This is connected directly to my wireless router, a Link sys EA6900. There are usually around 4 or 5 wireless devices in the house, such as smartphones, tables and laptops. Everything else in the house will use a wired connection.

On the ground floor, where the router is, I have a need to connect several wired devices - inyernet-connected TV, bluray player, Internet TV box, games console, etc.

On the upper floor is the home office, and this has the main PC, 2 network-connected printers, plus a QNAP NAS that uses 2 ethernet connections.

In the basement I have a home cinema & games room. This has an AV amplifier, bluray player and games console all of which need Internet access, plus another QNAP NAS that acts as a backup for the one on the upper floor.

I have 3 x TP-Link 16 port gigabit ethernet switches (TL SG-1016D). The plan is to locate a switch on each floor, each switch connected directly to one of the gigabit ports on the router. The switches on the upper and basement floors are connected via 20m ethernet cables, and the one on the ground floor via a 2m cable. All wired devices on each floor will be connected directly to the switch on that floor.

OK so that's the plan, but I'm having some issues.

I have the router connected to the modem. Wireless is up and running, and all devices can connect and have Internet access. I also have the switch on the ground floor connected to the router, and all devices connected to that switch have Internet access.

The problem comes when I try to connect another switch. It doesn't matter if it's the upper or basement switch, as soon as I connect it to the router, I lose both the wireless and wired access on the ground floor. Incidentally the same happens if I try to plug the upper/basement switches into the ground floor switch, instead of directly to the router.

Am I missing something here in my setup? It seems logical enough to me. Or am I just overloading the router?

Thanks in advance for any advice!

Keith

 

[jsmithepa]

Whatever you do, your devices must have ONE PATH to a destination, and not multiple paths. If u feel like posting a diagram, I can assist further.

 

[KeithOwen]

Essentially the setup is like this (ignoring the wireless devices which are obviously connected to the router)


_____First floor switch----First floor devices
/
Modem---Router----Ground floor switch----Ground floor devices
/
/_______Basement switch-----Basement devices

As I said, everything on the ground floor works fine, until I connect upper or basement switches

 

[KeithOwen]

Sorry the website has messed up the diagram. The three switches are all connected directly to the router

 

[Kewlx25]

What model switch and how are you connecting it? Can you graph your network topology?

 

[KeithOwen]

As I said in my original post, the switches are all TP-Link 16 port gigabit ethernet switches (TL SG-1016D). It's essentially modem direct to router, then it splits into three legs, with one switch to each floor

The three switches are directly connected to the router, and all wired evices are connected only to the switch on their floor

 

[Kewlx25]

As I said in my original post, the switches are all TP-Link 16 port gigabit ethernet switches (TL SG-1016D). It's essentially modem direct to router, then it splits into three legs, with one switch to each floor

The three switches are directly connected to the router, and all wired evices are connected only to the switch on their floor

My reading comprehension while watching TV is horrendous. Sorry. Not sure how I missed all of that obvious stuff.

Nothing immediately looks wrong. They're all unmatched dumb switches, so they don't do anything special. The only thing I can think of is a loop is being created some how.

Do the activity lights on your switch go crazy when you plug in the extra switch?

 

[jsmithepa]

Look pretty straightforward to me, am stumped.

Plug in the other switches, one by one, WITHOUT any client. I don't know what am trying to prove here, it's just a gut move.

 

[USAFRet]

So the "first floor switch" and the "basement switch" lead directly off the main router?
That should work, no problem.

As above, connect just the switches, with nothing else connected to them.
Let's go one part at a time.

 

[KeithOwen]

As I said in my original post, the switches are all TP-Link 16 port gigabit ethernet switches (TL SG-1016D). It's essentially modem direct to router, then it splits into three legs, with one switch to each floor

The three switches are directly connected to the router, and all wired evices are connected only to the switch on their floor

My reading comprehension while watching TV is horrendous. Sorry. Not sure how I missed all of that obvious stuff.

Nothing immediately looks wrong. They're all unmatched dumb switches, so they don't do anything special. The only thing I can think of is a loop is being created some how.

Do the activity lights on your switch go crazy when you plug in the extra switch?

No problem 🙂

The activity lights show traffic, and the devices can join the network, there's just no Internet access any more.

I'm going to try swapping a few cables/switches around to see what happens. I can't imagine a faulty port would make the router drop Internet access, but I'm prepared to try anything at this stage.

 

[KeithOwen]

So the "first floor switch" and the "basement switch" lead directly off the main router?
That should work, no problem.

As above, connect just the switches, with nothing else connected to them.
Let's go one part at a time.

Yes, I think that's my next step, cheers

 

[KeithOwen]

Whatever you do, your devices must have ONE PATH to a destination, and not multiple paths. If u feel like posting a diagram, I can assist further.

I didn't get the relevance of this comment at first, but after sleeping on it, it definitely helped me find the solution.

It seems like the idiotic installer (that would be me :lol managed to loop an ethernet cable from the switch, back into the same switch. Not only that, he did it twice, once on the first floor switch and once on the basement switch!

So I removed those spurious cables and, voila! Everything is now back online, and working as I originally anticipated. Thanks to everyone for their help, and especially to jsmithepa for pointing me in the right direction